1. Field of the Invention
This invention relates to simplifications in the construction of magnetic snap fasteners, and more specifically, to an interlocking magnetic fastener for use in garments.
2. Related Art
Overlapping flaps of clothing have traditionally been secured by the use of buttons. There has been much interest shown in developing simplified ways of doing this. The zipper was one of these. Using synthetic materials that stick together with tiny hooks and loops was another approach. Neither of these approaches overcame the difficulties experienced by those with limited manual dexterity, such as people suffering from arthritis, Parkinson's disease, muscular dystrophy, and other diseases. Using a zipper requires fine motor skills Hook and loop connectors, and mechanical snaps require strength and coordination to manipulate. Additionally, hook and loop connectors require hand and eye coordination to avoid misalignment.
Magnetic closures have been employed in purses, belts, and more recently, in clothing and they offer some significant advantages. They offer the potential of quick closure and simplified disengagement between two sheets of flexible material. Two magnets, each attached to one of the two sheets and oriented north pole of one to the south pole of the other, serve for this purpose. Alternatively, a magnet that attracts an opposing piece of ferromagnetic material achieves the same result.
In prior attempts to use magnets, a housing with a recess containing a ring magnet is attracted to either a second, similarly housed magnet or a disk of ferromagnetic material featuring a corresponding protrusion that enters the recess and is integral with the housing (see e.g., U.S. Pat. No. 5,722,126 to Reiter (1998)). The magnets in these fasteners need to be oriented and guided visually to achieve connection.
In order to secure these two magnet components to flexible material (e.g., fabric), several means were used historically, among these, screws, rivets and bendable legs. These means were either attached to or incorporated in the above-mentioned housings. Housings fastened in this way can cause discomfort when sharp edges contact the body, and such housings were not generally attached to woven textiles, which form the bulk of clothing worn. Additionally they were complicated and costly to manufacture, and therefore, mostly used in belts and purses. Such fastening methods are found it prior art U.S. Pat. No. 5,722,126 to Reiter (1998), U.S. Pat. No. 5,987,715 to Kohn (1999), and U.S. Pat. No. 7,178,207 to Wong et al. (2012).
Some of these housings both incorporated ring magnets and featured a central aperture with holes for thread, allowing for these housings to be sewn to material, such as cloth. The several metal pieces used to encase many of these closures required complex machine fabrication and assembly and the resulting closures were heavy. Additionally, the combined thickness of two connected housings occupied a space of some size and a gap resulted. This gap rendered them disadvantageous to use in shirts and pants, where, in addition to presenting an unusual appearance and compromising intimacy, the gap allowed the entry of cold air. See, e.g., U.S. Pat. No. 5,722,126 to Reiter (1998), and U.S. Pat. No. 7,178,207 to Wong et al (2012).
None of the art previously cited could be advantageously retrofitted into existing clothing. Additionally, none is suited for incorporation in conventional, textile-based clothing, which comprises the majority of clothing currently worn.
It has been difficult in past to create a suitably thin housing for fastening clothing magnetically because magnets have been retained by either a thickening of the housings or by partitions that enclose them. This disadvantageous thickening or partition prevents direct contact between two surfaces attracted magnetically, requiring the magnets used to be of larger size to compensate for this lack of direct contact, further increasing the overall size and weight. See, e.g., U.S. Pat. No. 6,215,381 to Aoki (2001) and U.S. Pat. No. 6,226,842 to Wong (2001).
Magnets sewn into opposing textile pockets have been recently introduced in an effort to reduce thickness and unsightly appearance. This particular form of connection carries with it a significant disadvantage. When subjected to lateral forces, slipping and disengagement of the two fabric surfaces occurs because there is no form of positive engagement of the magnets to prevent this from happening. Moreover, because at least two layers of textile separate the two magnets from contact, magnets of size large enough to overcome this separation must be used. Clothing that incorporates fasteners of this type may not be worn by people using pacemakers, another disadvantage. There is reference to such fasteners in non-patent literature, Alex Greig, Wife of Parkinson's Sufferer Invents Magnetic Shirt Which Closes Buttons Automatically, Daily Mail.Com (Jul. 4, 2013) as well as in U.S. Patent 2014143985 to Horton.
Thus, a need exists for a new and improved fastener for use in garments that address the problems detailed above.